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The arch of the aorta lies within the mediastinum. At the cellular level, the aorta and the aortic arch are composed of three layers: The tunica intima , which surrounds the lumen and is composed of simple squamal epithelial cells; the tunica media , composed of smooth cell muscles and elastic fibers; and, the tunica adventitia , composed of ...
The first and second arches disappear early. A remnant of the 1st arch forms part of the maxillary artery, [3] a branch of the external carotid artery. The ventral end of the second develops into the ascending pharyngeal artery, and its dorsal end gives origin to the stapedial artery, [3] a vessel which typically atrophies in humans [4] [5] but persists in some mammals.
Considerable anatomic variation exists in the circle of Willis, with classic anatomy seen only in about one-third of people. [4] In one common variation the proximal part of the posterior cerebral artery is narrow and its ipsilateral posterior communicating artery is large, so the internal carotid artery supplies the posterior cerebrum; this is ...
When the stroke is part of a lowercase [4] and rises above the height of an x (the x height), it is known as an ascender. [7] Letters with ascenders are b d f h k l. A stroke which drops below the baseline is a descender. [7] Letters with descenders are g j p q y. An arching stroke is a shoulder as in the top of an R or sometimes just an arch ...
It is the first branch of the aortic arch. [3] Soon after it emerges, the brachiocephalic artery divides into the right common carotid artery and the right subclavian artery. [4] There is no brachiocephalic artery for the left side of the body. The left common carotid artery and the left subclavian artery come directly off the aortic arch.
[3] [4] [5] He declared that the aim of the journal was to unite the branches of clinical medicine, pathological anatomy, and physiology. [6] [7] The first issue was published in February 1847 and contained only four articles – two by Virchow, one by Reinhardt, and one by Rud Leubuscher – and written entirely in German. [8]
The system relies on specialized neurons, known as baroreceptors, chiefly in the aortic arch and carotid sinuses, to monitor changes in blood pressure and relay them to the medulla oblongata. Baroreceptors are stretch receptors and respond to the pressure induced stretching of the blood vessel in which they are found.
Opisthotonus or opisthotonos (from Ancient Greek: ὄπισθεν, romanized: opisthen, lit. 'behind' and τόνος, tonos, 'tension') is a state of severe hyperextension and spasticity in which an individual's head, neck and spinal column enter into a complete "bridging" or "arching" position.